Abstract Details
Abstracts
Author: Norman M. Cao
Requested Type: Poster
Submitted: 2025-03-13 17:15:32
Co-authors: D.Qi
Contact Info:
University of Texas at Austin
1 University Station, C1500
Austin, TX 78712
United States
Abstract Text:
Turbulence in the tokamak edge and scrape-off-layer is often associated with large-amplitude, intermittent fluctuations that resist description by standard weak turbulence theories.
In this work, we focus on turbulence dominated by Lagrangian coherent structures, a particular class of fluctuations that offer a promising avenue for understanding plasma dynamics in strong turbulence regimes. We present progress on studying such structures using the stochastic Lagrangian description of turbulence, based on the Feynman-Kac formula, designed to take advantage of statistical correlations imparted into the flows by Lagrangian coherent structures. First, we demonstrate how stochastic Lagrangian methods can be used to diagnose coherent structure formation in the Hasegawa-Wakatani equations, showing how turbulent mixing can, counterintuitively, reinforce rather than destroy coherent structures. Second, we develop a framework for computing turbulent fluxes using stochastic Lagrangian trajectories and discuss how these formulas generalize information from the linear cross phase to large Kubo number regimes, where the assumptions of quasilinear theory break down. Finally, we describe progress towards the characterization of Lagrangian coherent structures in gyrokinetic phase space and discuss their potential impact on transport driven by drift wave turbulence in the presence of zonal flows.
Characterization: 7.0
Comments: